This image, taken from NASA’s Terra spacecraft on November, 13, 2011, shows a major rift in ice. At the time this photo was taken, scientists said that the crack, which extended for 19 miles and is 260 feet wide by 195 feet deep, would eventually calve a giant iceberg measuring some 350 square miles. The iceberg now is estimated to cover 270 square miles. Photo: NASA
Researchers in the UK say they are closely monitoring a massive iceberg that recently broke off from Antarctica, but not because of the ramifications it has on climate change, rather due to the dangers it poses to ships.
Dr Robert Marsh, a researcher from Ocean and Earth Science at the University of Southampton, is part of a team of scientists that has been helping track the Singapore-sized iceberg which broke off in July from the Pine Island Glacier in Antarctica and now poses a threat to shipping lanes in the Southern Ocean.
“The primary reason to monitor the iceberg is that it’s very large. An iceberg that size could survive for a year or longer and it could drift a long way north in that time and end up in the vicinity of world shipping lanes in the Southern Ocean,” explains Dr Marsh, who is an investigator on the project and based at the National Oceanography Centre in Southampton.
“There’s a lot of activity to and from the Antarctic Peninsula, and ships could potentially cross paths with this large iceberg, although it would be an unusual coincidence,” adds Marsh.
The Natural Environment Research Council (NERC) has just agreed to fund an emergency grant that will let researchers track and predict the iceberg’s path, preventing it from becoming a maritime hazard.
Scientists from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research discovered the crack in the glacier and have been following the calving event via the earth observation satellites TerraSAR-X from the German Space Agency (DLR). They have been documenting the changes in the ice through many individual images that are currently providing data on how the iceberg is traveling. Globally, icebergs of this size break off of glaciers on average every two years, but until now there has been no attempt to track and predict their path.
The team will use their results to more accurately model the paths of future large icebergs, which are likely to become more common as global warming encourages glacier calving. The large amounts of freshwater released by the iceberg as it melts could also affect the ocean currents.
“If the iceberg stays around the Antarctic coast, it will melt slowly and will eventually add a lot of freshwater that stays in that coastal current, altering the density and affecting the speed of the current. Similarly, if it moves north it will melt faster but it could alter the overturning rates of the current as it may create a cap of freshwater above the denser seawater,” says Professor Grant Bigg of the University of Sheffield, principal investigator on the grant.
“This glacier is not large enough to have a big impact, but it could have an effect. Particularly if these events become more common, there will be a build-up of freshwater which could have lasting effects,” he concludes.
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